ALEXANDRA Richards has places to be. The rock heiress/model/deejay was hired to spin at the opening of stylist Jordan Blackmore‘s Three Squares Studio last week for three hours, but left after 38 minutes to have dinner with friends. According to a source, “Her agent requested payment for the full three hours she was contracted to play, but the salon balked. They ended up negotiating payment per minute.” Richards couldn’t be reached. A rep for the studio says, “I guess dinner was more important than her contract.”